Improvement in pitman and crank motions



Q. A. THGMAS.

Pitman and Crank Motion. y N0.l47,803. ParentedFeb.24.1874.

UNITED STATES PATENT OFFICE.

oUiNoY A. THOMAs, oF OXFORD, MICHIGAN,

IMPROVEMENT IN PITMAN AND CRANK MOTIONS.

Specification forming part of Letters Patent No, 147.803, dated February 24,1674 applicationled August 2, 1873.

Oxford, county of Oakland and State of Michigan, have invented certain Improvements in Iitman and' Crank Motion, of which the following is a specification:

X Y Z represent a fly-wheel. T and U represent two pitmen attached to the common wrist D; I J K, a ange Or band secured to the spokes of the ily-wheel; A B and A C, two levers attached to the common center A, and secured to the pitmen T and U at the points w zo; l 2 3, the can of pivot, around which oscillate the levers A B and A C Within the limits of the dotted arcs O N and L M; G and H, two pawls, secured to the levers A B and A (l at the points a and b; E and F, two springs; 'V NV, slot in which to insert screw-driver 4 and 5, projections from pitmen T land U.

"When the pitmen T and U are forced upward in the direction ot' I), the pawl H is thrown by the spring E against the inner surface of the flange I J K at the point c, and iirmly stayed` by means of the toggle-joint formed by the leveil A B and the pawl H in the angle A b c, forced into action by the pit man U, and carrying with it the iiy-wheel in the direction of the arrows R and S. While the pitlnan U is thus acting, the pitman T forces the toggle-joint A a. d in a device exactl y similar to that attached to the pitman U, already described, in an opposite direction, relieving the pawl G. W'hen the Wrist D reaches a point, P, and the levers B and C the points 0 and L, the two pitmen T and U come in contact at the projections 4 and 5,'arresting farther progress in the direction of l?, relievE ing by their contact the pawl H. When the motion of the pitman is reversed in the direction of Q, the pawl G is brought to act in a manner similar to th at already described by the `pitman T, and the pawl H is relieved at the same time, carrying the fly-wheel in the directionw indicated by the arrows It and S. When the wrist l) reaches the point Q, and B and C reach M and N, the motion of the pitmen is wrist of the pitman, so that the lever holding the friction-pad which is brought in contact with the rim of the wheel is made so short that the purchase is too short to give bite enough to cause the device to act at all times; and such construction I do not claim; but

vVhat I claim, and desire to secure by Letters Patent, is

The combination of the pitmen T and U,

pivoted to the levers A C and A B at w and w, the pawls G and H, pivoted at thepoints a and b', with springs E and F, substantially as and forthe purposes hereinbefore set forth.

l Q. A. THOMAS. Witnesses WM. HEMINGWAY, W. W. STIOKNEY. 

